1. Technical Field
The present disclosure relates to a wiring board having high-density fine wiring.
2. Background
In recent years, as electronic devices typified by portable communication devices and music players have become more miniaturized and highly functionalized, electrodes of semiconductor elements used in these electronic devices are formed with small diameter and high density. Correspondingly, smaller diameter and higher density are in progress also in semiconductor-element connection pads of wiring boards. For this reason, when the semiconductor element is connected to the wiring board, it is important to connect the electrode and the semiconductor-element connection pad corresponding to each other accurately and reliably by reduction in the thermal expansion and contraction difference between the two. In order to reduce such a thermal expansion and contraction difference, dispersing insulating particles in build-up insulation layers at high density to reduce the coefficient of thermal expansion of the wiring board may reduce the difference in the coefficients of thermal expansion of the wiring board and the semiconductor element. Such a wiring board is described, for example, in Japanese Unexamined Patent Application Publication No. 2004-207338.